Medications accidentally left within reach of unsupervised young children result in all too many emergency hospitalizations every year as a result of overdose consumption of such medications. To minimize such incidents various child resistant closures have been developed which require a degree of adroitness not usually found among small children but within the capability of an ordinary adult.
The invention described here is one such child resistant closure suitable for liquid medications such as cough syrup and other medications which although readily available may contain ingredients which can be harmful if taken in quantities beyond a recommended dosage.
Liquid medications are commonly administered to children using disposable oral syringes which allow a dose to be carefully measured and conveniently delivered to the child's mouth. The oral syringe has a syringe barrel with a narrow orificed tip at one end and an opposite open end in which slides a plunger used to draw liquid through the tip into the barrel, and to expel the liquid for delivery from the barrel through the tip into the child's mouth.
In certain prior child resistant caps for such applications a cap was provided with an elastomeric self-reclosing septum, sometimes precut with a short slit through the septum center, such that the tip of an oral syringe can be pressed through the septum into the medication bottle and a dose of the liquid drawn into the syringe. When the syringe is withdrawn from the septum the septum recloses. While such elastomeric closures provide a degree of protection for small children against access to the bottle contents, a further degree of protection is desirable.
Child resistant bottle caps have been developed in an ongoing effort to prevent accidental overdosing of children with household medications. Exemplary of such caps are those having two caps one mounted over the other. The inner cap is engaged as by threading to the neck of the medication bottle and the two caps are constructed such that turning force is transmitted from the accessible upper cap to the underlying inner cap only by application of some additional force such a downward pressure or radial compression to the upper cap. Failing such additional force the upper cap merely turns freely on the inner cap and the inner cap does not release from the bottle neck. The safety cap is designed such that a young child either lacks sufficient strength or manual dexterity to open a medication container provided with such safety cap.
A continuing concern relates to the possibility that a child resistant cap could become detached from the medication bottle as a result of sideways bending or tearing of the cap assembly until it actually breaks off from the neck of the bottle, possibly resulting in unrestricted access to the bottle contents.
This invention addresses this risk by providing a fail-safe breakaway feature which preserves closure and keeps the bottle or container sealed against access to its contents in the event that the child or tamper resistant cap is broken or torn away.
The improved safety cap has an upper portion which carries a child resistant cap, which may be of any design configured to resist opening by a typical young child, mounted to a lower portion which is securely attached to the bottle. A cap conduit passes through both the lower and upper portions of the cap and is open at a lower end to the interior of the bottle or container and terminates at an upper end in a discharge opening. The upper portion is attached to the lower portion of the cap assembly through a break-away connection designed and constructed so as to preferentially break or separate when a sufficient bending or twisting force is applied to the upper portion relative to the lower portion. The break-away connection is selectively weakened by design to fail before the lower portion becomes separated from the bottle neck or container.
An inner closure is provided in the lower portion for normally closing the conduit to flow of liquid from the bottle interior. The inner closure may be of a self-resealing type. For example, the inner closure may be an elastomeric septum configured to allow passage of a liquid transfer implement such as the tip of an oral syringe by distending and then returning to a substantially sealed condition following withdrawal of the syringe tip.
The lower portion may be attached to the container or bottle by any means sufficiently resistant to separation. For example, the lower portion may be a plug of elastomeric material tightly press fitted into the neck of a medication bottle to resist extraction from the bottle neck by any force lesser than required to cause separation of the upper portion through physical failure of the break-away connection. Alternatively, the lower portion may be formed integrally in one piece with the container or bottle neck.
The break-away connection can be constructed in a variety of ways. For example, a mechanical connection using resilient interlocking parts of a suitable plastic resin or elastomer may be provided so as to separate by resilient deformation of the interlocking parts under sufficient strain applied to the upper portion, thereby freeing the upper portion from the lower portion. In another form of the invention the upper and lower portions may be joined by an adhesive selected to fail preferentially at the adhesive junction in response to application of sufficient bending, pulling or twisting force to the upper portion, releasing the upper portion to leave the lower portion in the bottle neck or other opening of the container.
The inner closure provided for closing the portion of the conduit passing through the lower portion remains in place following detachment of the upper portion, and effectively continues to seal the container against access to its contents.
In normal usage of the cap assembly here described an adult or supervising user actuates the child resistant cap on the upper portion of the assembly to gain access to the upper end of the conduit. A liquid transfer implement such as the tip of an oral syringe or a pipette is introduced into the conduit and passed through the inner seal to enter the medication container. A medication dose is drawn into the implement which is then removed from the cap assembly, allowing the inner seal to return to a substantially sealed condition.